Sucralose,
Chemical name: 4,1′,6′-trichloro-4,1′,6′-trideoxygalactosucrose;
English name: 4,1′,6′-tricholorgalacosucrose (sucralose);
Structural formula:

Sucralose, which is a novel non-nutrition sweetener with high sweetness that is as 600 times as that of sucrose, becomes the ideal sweet substitute for the diabetes patients and has been permitted by more than twenty countries to be used as a food sweetener, because it does not participate in metabolism, is not absorbed by human body, is not utilized by the dental caries bacteria, or does not cause dental caries.
At the beginning, sucralose was successfully prepared by Tate & Lyle Company, UK in 1975 by using chemical synthesis. This chemical synthesis method mainly includes monogroup protected synthesis and hologroup protected synthesis, both of which use sucrose as a raw material.
Monogroup protected methods, such as the acetate method reported in U.S. Pat. Nos. 4,889,928 and 5,449,772 and the dibutyltin oxide method reported in U.S. Pat. Nos. 5,023,329 and 4,950,746, use the sixth site hydroxyl group that is more active in sucrose molecule. The hydroxyl group on the sixth site is protected selectively by acetyl group or benzoyl group to prepare sucrose-6-acetate or sucrose-6-benzoylester, then the sucrose-6-acetate or sucrose-6-benzoylester is chlorinated selectively by VILSMERIER agent to obtain trichlorosucralose-6-acetate (benzoylester), and finally the sucralose is obtained after hydrolysis.
Hologroup protected methods, such as the method reported in U.S. Pat. Nos. 4,783,526; 4,801,700; 4.343.934; and 4,362,869, use the difference in the steric hindrance amongst the eight hydroxyl groups in the sucrose molecule, which is to say, use one group with larger volume to selectively protect the to primary hydroxyl group with a smaller steric hindrance, then the remaining hydroxyl groups are totally acetylated, and then the protecting group is removed under acidic conditions. The acetyl group on the fourth site is transferred onto the sixth site so that the three chlorinated sites meet certain requirements. Then three hydroxyl groups are chlorinated, and the sucralose is obtained by hydrolysis and deacetylating.
CN03126655.X discloses a method for synthesizing sucralose, characterized in that sucrose as a raw material is subjected to transesterification with ethyl acetate in a solution of N,N-dimethylformamide and in the presence of a sulfate solid acid catalyst or a sulfate solid acid catalyst adsorbed on the macromolecular carriers to produce sucrose-6-acetate, which is subjected to chlorination and alcoholysis to give sucralose.
CN03805527.9 discloses a novel extracting method for purifying sucralose.
CN200610034731.3 discloses a method for preparing sucralose, comprising firstly preparing sucrose-6-ester in a separate-type electrolyzer device using indirect electrooxidation synthesis technique, and then chlorinating and hydrolyzing sucrose-6-ester to produce sucralose.
CN200710037102.0 discloses a method for preparing sucralose, comprising reacting sucrose with an acetylating agent in the presence of a polymer loaded organotin catalyst to produce sucrose-6-ester with high chemical purity, and then chlorinating and alkali hydrolyzing sucrose-6-ester to produce sucralose.
Among these synthesis methods, the hologroup protected methods including too much procedures, are relatively complicated and quite high in cost; whilst the monogroup protected methods for synthesizing sucrose-6-acetate are low in chemical yield, and are difficult and complex to purify the water phase of the product, and are not desirable in the purity of product. For the dibutyltin oxide method, since the dibutyltin oxide used as a catalyst is not able to recycle, the production cost is high and the product is not suitable for application due to the presence of tin-based impurities.